Many network content browser applications (also referred to simply as “browsers”) allow multiple content items to be open concurrently. For example, users can open multiple browser windows or browser instances, with each window corresponding to a different content item, a different instance of the same content item, or some combination thereof. Each browser instance is typically managed as a separate process on a user computing device, with its own separate memory space in which objects of the content page are stored. As another example, users may open multiple “tabs” within a single browser window or instance, with each tab having a corresponding content display pane. As with the separate window example above, the separate tabs are typically managed as separate (or substantially separate) processes on the user device, with each tab corresponding to a separate memory space on the user device.
Due to the finite amount of memory available on user devices, the number of browser instances or tabs that may be concurrently open is also finite. Some browser applications address this limitation by allowing users to open a relatively large number of browser tabs concurrently such that the maximum number of concurrent browser tabs may appear to users to be nearly infinite. When a user device runs out of memory for additional browser tabs, the browser can close (or destroy, de-allocate, decommission, etc.) a browser tab to free up memory while continuing to display an indication that the browser tab is available (e.g., display the “tab” portion of the browser tab, without a corresponding content display pane). Subsequently, when a user wishes to return to a previously opened tab that has been closed (or destroyed, de-allocated, decommissioned, etc.), the browser application can retrieve and reload the corresponding content item from a content server and display the content item again for the user.